Die for hot-pressing powdered metal



Aug. 19, 1969 R E. mcg ETAL 3,461,506

DIE FOR HOTITPRESSING POWDERED METAL I med April 2e. 1967 eo hfarre l yzM law United States Patent O U.S. Cl. 18-47 5 Claims ABSTRACT OF THEDISCLOSURE A die having an inner surface which does not adhere topowdered metal when compressed under high pressure and temperature.

In the use of powdered metal for making articles it is customary tocompress the powder in dies under high pressure and temperature. Howeverdifculty has been experienced due to the powder sticking to the innersurfaces of the dies even when the dies are made of tungsten carbide.This results not only in imperfect articles but also in rapiddeterioration of the dies.

Objects of this invention are to overcome the aforesaid ditiiculty andto provide a die in which there is no tendency to weld, gall or scoreeither the die or the compacted article.

The present invention involves the discovery that titanium carbide isunique in that it affords dies which avoid all tendency to adhere to thecompacted articles. The titanium car-bide is preferably bonded withsmall amounts of nickel or cobalt or both, e.g., to the extent of about3 to 12 percent by weight.

While the walls of the dies may consist of titanium carbide, the dieswould then be unduly costly. Consequently the walls are preferably madeof some other material, such as tungsten carbide, and then lined withtitanium carbide. This can be done by making a thin liner to fit the dieor by vapor disposition in well-known manner.

For the purpose of illustration a typical embodiment of the invention isshown in the accompanying drawings in which FIG. 1 is a longitudinalaxial section; and

FIG. 2 is an end view.

The particular embodiment chosen for the purpose of illustrationcomprises a cylinder made of tungsten carbide 3,461,506 Patented Aug.19, 1969 "ice in three sections 1, 2 and 3 to facilitate finishing theinner surface of the die before the sections are assembled. To hold thesections together the die is wound with Wire 4 having a thermalexpansion coefiicient closely matching that of the die, such as tungstenor molybdenum, as disclosed and claimed in the copending application ofRichard E. Rice, Sr., No. 633,780, tiled on even date herewith. Theinner surfaces of the sections are lined with surfaces 5 of titaniumcarbide as above described.

In use the powdered metal is compressed between two plungers 6 and 7 inusual manner. To charge the die with powdered metal the upper plunger 6is Withdrawn as shown in FIG. l, and to expel the compacted article theupper plunger is Withdrawn and the lower plunger is advanced.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsand equivalents which fall within the scope of the appended claims.

We claim:

1. For making articles by hot-pressing powdered metal, a die having aninner surface consisting principally of titanium carbide.

2. A die according to claim 1` wherein said surf-ace comprises a liner.

3. A die according to claim 1 wherein said surface comprises a vapordeposition.

4. A die according to claim 1 wherein said surface also comprises nickelor cobalt or both.

5. A die according to claim 3 wherein the body of the die consists oftungsten carbide.

References Cited UNITED STATES PATENTS 3,067,465 12/ 1962 Giardini etal. 3,061,877 11/1962 Custers et al. 3,084,388 4/ 1963 Ballhausen18-16.5 3,085,291 4/1963 Hals etal 18-16.5 3,088,170 5/ 1963 Strong.3,213,491 10/1965 Craig. 3,329,513 7/1967 Murata et al 264-332 X I.HOWARD FLINT, JR., Primary Examiner U.S. C1. X.R.

